Heat-shock protein 25 induction and redistribution during actin reorganization after renal ischemia.
The small heat-shock proteins appear to have a regulatory role in actin dynamics. Since cytoskeletal disruption is integral to ischemic renal injury, we evaluated expression and intracellular distribution of heat-shock protein 25 (HSP-25) in rat renal cortex after 45 min of renal ischemia. HSP-25 was constitutively expressed and induced by ischemia with peak levels reached by 6 h reflow. Ischemia caused a shift of HSP-25 from the detergent-soluble into the insoluble cytoskeletal fraction. By 2 h reflow, the majority of HSP-25 had redistributed into the soluble fraction. HSP-25 was predominantly localized in a subapical distribution in control proximal tubules, a pattern intermediate between deoxyribonuclease (DNase)-reactive and filamentous actin. After ischemia, HSP-25 dispersed through the cytoplasm with small punctate accumulations similar to DNase-reactive actin. During later reflow, all three proteins were found in coarse intracytoplasmic accumulations; however, HSP-25 and DNase-reactive actin were in separate accumulations. HSP-25 and microfilamentous actin staining returned to the subapical domain. Thus the temporal and spatial patterns of HSP-25 induction and distribution suggest specific interactions between HSP-25 and actin during the early postischemic reorganization of the cytoskeleton. HSP-25 may have additional roles distinct from actin dynamics later in the course of postischemic recovery.
Aufricht
C
C
Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06520-8064, USA.
Ardito
T
T
Thulin
G
G
Kashgarian
M
M
Siegel
N J
NJ
Van Why
S K
SK
D000199:Actins / Q000378:metabolism*; D000818:Animals; D001012:Aorta, Abdominal; D003599:Cytoskeleton / Q000378:metabolism / Q000473:pathology; D006360:Heat-Shock Proteins / Q000096:biosynthesis* / Q000378:metabolism; D007511:Ischemia / Q000378:metabolism* / Q000473:pathology; D007668:Kidney / Q000098:blood supply* / Q000378:metabolism / Q000473:pathology; D007687:Kidney Tubules, Proximal / Q000378:metabolism / Q000473:pathology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012077:Renal Artery
D000199:Actins; D006360:Heat-Shock Proteins